How to Vent a Floor Drain

It’s an unfortunate reality that they are often not installed correctly when it comes to floor drains. This can lead to issues with water pooling in the basement or other places on your property. For this reason, it is important to understand how to vent a floor drain, so you don’t invite any unnecessary problems into your home. 

One of the most common ways to vent a floor drain is by installing either a PVC pipe or metal ducting at the outlet of the trap and running it up through ceiling joists and out over the roofline for 6-12″ above grade. Of course, before cutting any holes in drywall, be sure that there are no wires or pipes in that area that could cause damage during installation!

10 Methods on How to Vent a Floor Drain

1. PVC Pipe Venting Method: 

The PVC Pipe Venting Method involves cutting a 14″ long section of 4″ diameter PVC pipe and attaching it to the bottom side of your floor drain with a pair of threaded adapters. If there is not 4″ of ceiling space above your drain, you may need to use a section of 3″ PVC pipe instead.

2. Copper Venting Method: 

The Copper Venting Method involves cutting a 36″-48″ piece of 1/2″ copper tubing and bending it into an inverted U-shape (see illustration below). This tubing must be long enough to reach from the floor drain up through the ceiling joists. Once it has reached the desired height, solder a threaded adapter to each end of the tube and attach it to your floor drain with two 3″ – 4″ screws.

Check it out to learn to fix a floor joist that has been cut.

3. Metal Duct Venting Method: 

The Metal Duct Venting Method involves cutting a section of galvanized metal ducting 10-12″ long and attaching it to the bottom side of your floor drain with a pair of threaded adapters. However, if there is not 4″ of ceiling space above your drain, you may need to use a section of 3″ or 2″ metal duct instead. You can find metal ducting at most hardware stores.

4. Garage Vent Method: 

The Garage Venting Method involves cutting a hole in the side of your garage and attaching a section of large-diameter PVC sewer pipe to the floor drain with threaded adapters. To find out how big you need to cut this hole, simply measure the diameter of your sewer pipe and multiply it by pi (3.14). You should then remove the cap on your floor drain and measure the diameter of the hole that it sticks out of to ensure you do not cut your hole any larger than necessary.

5. Trench Method: 

The Trench Venting Method involves cutting a trench in the ground around your house so that one end of your drainage pipe (the one attached to your floor drain) is below the frost line. Fill this trench with washed rock and then attach a section of large-diameter PVC sewer pipe, capped at both ends, to your floor drain with threaded adapters.

6. Pipe Wrapping Method: 

The Pipe Wrapping Method involves wrapping the J-bend of the drain with some heavyweight (but flexible) plastic sewer pipe (such as Rhino Pipe). Then, attach a section of large-diameter PVC sewer pipe to your floor drain with threaded adapters. You can find sewer pipes (and other plumbing supplies) at most hardware stores.

7. Drywell Method: 

The Drywell Venting Method involves digging a dry well around your house and attaching a section of large-diameter PVC sewer pipe to your floor drain with threaded adapters. Then, fill the drywall back in with a washed rock unless you are reusing it for another purpose (such as watering plants).

8. Drown-proof Drywell Method: 

The Drown-proof Drywell Venting Method involves digging a dry well around your house and installing a perforated drain line with an access point inside the home. This is one of the most effective types of dry wells, but some local municipalities may have restrictions on installing buried drain lines.

9. Discharge Well Method: 

 The Discharge Well Venting Method involves digging a discharge well around your house and installing a perforated drain line inside it. However, if you live in an area with high local groundwater levels, this method may not suit your location.

10. French Drain Method: 

The French Drain Venting Method involves digging a trench around your house and installing a perforated drain line. Then, cover the entire area with washed rock and seal it off with landscape cloth before covering it again with soil. You can find landscape cloth and washed rock at most hardware stores.

This French Vent Installing a Perforated Drain Line

Tips and Tricks

  1. You can install the new vent line at any height, but it’s best to keep it under 6′. Also, always mark the wall where you plan to run the vent line before you drill.
  2. Cut the new PVC vent line at an angle, so water flows easily toward the floor drain.
  3. Taper the top of the vertical section to fit tightly in a 4″ ABS pipe stub-out.
  4. The bottom end is flared with pliers to fit tight against the collar on the new floor drain.
  5. Make any bends in the PVC with a tubing bender to maintain at least 1/4″ waterway all the way through.
  6. When connecting, wrap each threaded fitting with plumber’s tape in the direction of the thread- clockwise for male fittings, counterclockwise for female fittings.

Precautions and Warnings

  1. Shut off the electricity or gas to the area where you are working.
  2. Turn off any water supply to the area as well. If it is a basement, shut off the supply from the above-ground first. The last thing you would want is to flood your house while working on a drain!
  3. Use caution when working around water, sewage, and hazardous gases.
  4. Wear protective clothing such as rubber gloves, rubber boots, and eye protection if necessary.
  5. If you’re working outside in deep cold weather, be adequately dressed according to the conditions to avoid frostbite or hypothermia.

Why Is a Floor Drain Sometimes Wet Vented?

If there is no vent for a floor drain, the gravity flow of wastewater from fixture drains causes sewage gases to enter the building. Almost all plumbing codes now require a wet vent at each floor drain where multiple fixtures are connected.

Floor Drain Sometimes Wet Vented

The wet vent is usually directly above the floor drain and is attached with a PVC pipe. A floor drain that is wet vented can be installed in any area where there is no danger of floodwaters leaking into the building through the drain opening.

What Is a Dry Vent?

A dry vent allows waste to flow outside without using water in the system. When it has traps, piping is also called “wet venting” since the traps hold water to prevent sewer gas from backing up into the building. In a dry vent, no water is discharged along with wastewater. Instead, waste flows out of the drain opening following gravity’s downward pull.

The system is dry because it uses air instead of water to block sewer gases from backing up into the building. However, drain and vent piping must never contain air, so this system does not work without a device that allows wastewater to flow down while drawing in air from above.

Frequently Asked Question

Do Floor Drains Need a Vent?

Yes, a floor drain needs a vent. It is important to have floor drain vents because they provide protection for your basement or crawl space.

Floor drains are typically installed at the lowest point of your basement or crawl space and do not come with built-in vents. Floor drains require proper ventilation to prevent moisture from entering your home’s walls and insulation, which can lead to mold growth in your home’s crawl space.

A Floor Drain Needs a Vent

How Do You Vent a Basement Floor Drain?

A lot of people who have a basement floor drain will know that it is possible to vent the drain by pushing a pipe up through the roof. The pipe is then connected to an outdoor drainage system, and the water that drains from your basement drains outside.

However, there are some steps you should take before venting your floor drain so that you don’t get any problems:

  1. Make sure all water has been removed from the area before you start working on your basement floor drain. This includes any standing water in basements or other areas where the water could collect.
  2. Have someone help you lift up your garage door so that they can watch for any cars driving into your driveway, as well as watch for children playing in the area.
  3. Make sure you have enough hose and plumbing supplies available to finish venting your basement floor drain with ease, such as fittings, clamps, valves, pipes, etc.

What Happens if A Drain Is Not Vented Properly?

If a drain is not vented properly, then the water will back up into the toilet, and that can cause a flood. This would cause damage to your property, the surrounding area, and health risks for you and your family.

How Do I Know if My Basement Drain Is Vented?

To know if your basement drain is vented, you should:

A Floor Drain Needs a Vent
  1. Take a shower or bath in the bathroom sink to make sure there is enough water flow to the vent pipe.
  2. If there is no water flow, open up the cabinet under the sink and look for any cracks or holes that might be leaking air into the pipe.
  3. If there are no leaks, remove all of the vent covers from around your home and check for blockages in each one.

How Do You Tell if A Drain Is Properly Vented?

First, you need to know what a vent is. A vent is a pipe that goes through the roof of your house and out into the attic space above it. It’s there to allow excess water vapor from inside your home to escape before it reaches the attic and starts damaging things like insulation, wiring, or drywall.

Next, you need to know how often you should be checking for leaks in your vents. You should check them at least once every year and more often if there are signs of moisture problems or mold growth.

Where Are Floor Drains Required?

Floor drains are required in the following places:

  1. On a slope or curb where the water flows downhill and collects, such as at the base of a gutter or drain pipe that feeds into a larger storm sewer system.
  2. In areas where there is flooding, such as under street-level car parking lots or near building foundations.
  3. Around swimming pools to prevent pooling of water on paved surfaces from rainwater runoff, which can lead to puddles and wet floors and cause health problems if not drained properly.
You Tell if a Drain Is Properly Vented


If you are looking for advice on how to vent a floor drain, we hope this article has been helpful. We know that there is no one size fits all solution and recommend getting professional help if the problem persists. The most important thing to remember is not to panic; it’s always better to be safe than sorry!

You may read also – How to keep basement floor drains from smelling

Smart Home Pick